Scientists discover 64,000 square miles of heat-resistant coral reefs in 71 countries that could help protect world oceans for decades

Coral reefs in the southern Andaman Sea, Southeast Asia Cavan Images

An international team of scientists has mapped more than 64,000 square miles of coral reefs that can withstand severe heat stress. The findings provide vital plans for saving marine life at a time when the world’s oceans are experiencing the worst bleaching crisis on record.The study used artificial intelligence to analyze decades of environmental data. AI identified specific underwater protected areas in 71 countries and 100 regions. These areas have unique natural features that can protect, insulate or help coral ecosystems recover from marine heat waves.The research was presented at the Our Oceans conference in Mombasa, Kenya, and posted on the preprint server EcoEvoRxiv. The findings challenge the common scientific belief that coral reefs cannot be saved. Instead, the new map shows exactly where governments should invest conservation dollars to protect marine life.“Coral reefs are often viewed as ecosystems that cannot be saved,” study co-author Emily Darling, director of coral conservation at the Wildlife Conservation Society, told the conference. “This study shows that’s not the case.”

Use your computer to find climate protected areas

Coral reefs cover only 1% of the ocean floor, but support a quarter of all marine life. They are vital to the global food supply and protect coastlines from storms. Their biggest threat is rising water temperatures, which can lead to mass bleaching.When water gets too hot, corals expel the tiny, colorful algae that live in them. This deprives the coral of its main food source. It leaves them pale, stressed, and likely to die of starvation or disease.To find habitats that can survive such high temperatures, researchers have defined three types of natural refuges, called climate refugia:

Darling and her team trained an artificial intelligence model to find these three types of shelter. They fed the computer some 45,000 coral observations recorded since 1960. The system studied 42 independent environmental factors, including water chemistry, temperature changes and local human activity.AI models evaluated global maps to predict coral health in 2050. The results show that these resilient reefs are highly concentrated. About 61% of these safe zones are located in the waters of five countries: Australia, the Bahamas, Cuba, Indonesia and the Philippines.The models also discovered new, highly resilient reef areas in Belize, Nicaragua and the Turks and Caicos Islands. This extends data from the 2018 “50 Reefs” study, the first major effort to find heat-tolerant corals.

Coral reefs and their associated ecosystems

Targeted Conservation Funding Program

Finding these specific areas could provide environmental groups with a clear plan. This is particularly helpful for small island nations that don’t have the money or resources to protect all of their waters.“Climate-resilient coral reefs are not evenly distributed,” study co-author Joseph Maina, an environmental scientist at Macquarie University in Australia, told the conference. “Countries need to understand…these differences so that they can take this uneven distribution into account when planning where future conservation investments will go.”Independent scientists welcomed the accuracy of the new data. They note that it shifts the focus from simply documenting the destruction of the ocean to actively saving it.“This study adds to decades of work on the resilience of coral reefs to climate change,” said marine ecologist David Obura, chair of the Intergovernmental Platform on Biodiversity and Ecosystem Services, who was not a member of the research team. “It focuses attention on a key question: Will climate protected areas be 10%, 1%, or even less than the size of previous coral reefs?”However, local environmentalists in these newly discovered safe zones say the results must be treated with caution. Alizee Zimmermann, executive director of the Turks and Caicos Coral Reef Fund, wanted to scrutinize the data because of the lack of long-term monitoring in her region. She warned that the good news should not allow governments to become complacent.“Claims of Caribbean coral reef ‘death’ are inaccurate and could undermine progress in coral reef restoration and conservation initiatives in the region,” Zimmerman said. “However, it would be equally disingenuous to say they are thriving.”

Background of global destruction

The discovery of these stretchy pockets comes at a critical time. According to a report by the National Oceanic and Atmospheric Administration (NOAA) and the International Coral Reef Initiative, more than 80% of the world’s coral reefs have suffered bleaching-level heat since 2023. This makes it the worst global bleaching event in history.Mass death strikes the tropics. Florida’s coral reefs suffered severe heat in 2023, causing 100% coral reef bleaching in the Florida Keys. In 2024, Australia’s Great Barrier Reef faces catastrophic bleaching. Vast areas of the Persian Gulf, Red Sea and Caribbean Sea also suffered severe damage.The current crisis has surpassed the record set between 2014 and 2017, when 70% of the world’s coral reefs were exposed to extreme heat. Melanie Macfield, founder of the Healthy Reefs for Healthy People initiative, described the eerie sight of heat-damaged coral reefs.“There are usually no swimming fish and no bright colors on the reef,” McField said. “In what should be a noisy, vibrant reef landscape, there is a pallor and silence.”

Navigating uncharted waters

With the current marine heat wave still occurring, scientists don’t know when water temperatures will drop enough for corals to heal.“We may never see the thermal stress that causes bleaching drop below the threshold that triggers a global event,” warns Mark Eakin, communications secretary for the International Coral Reef Society. “We are looking at something that will completely change the face of the planet and the ability of the oceans to support life and livelihoods.”Britta Schaffelke, a researcher at the Australian Institute of Marine Science, agrees that the sheer scale of the heatwave has pushed marine ecosystems into completely uncharted waters.However, proponents of the new mapping study point out that corals have survived major extinctions in Earth’s history. If these specific safe zones are protected from overfishing and pollution, corals can eventually spread and repopulate other areas.“The ancestors of today’s corals survived the asteroid impacts that wiped out the dinosaurs on land and many creatures in the oceans,” said Joerg Wiedenmann, a marine biologist at the University of Southampton. “So if we manage to reduce ocean warming, there’s always a chance that corals can recover.”In the long term, saving these newly mapped areas depends on global political action to reduce greenhouse gas emissions. Valeria Pizarro, senior coral scientist at the Perry Institute of Marine Science, stressed that world leaders must invest heavily in clean energy and reduce the use of fossil fuels to give these protected areas a real chance.However, these protections face immediate political obstacles in the United States, where the Trump administration has moved to increase fossil fuel production and reduce clean energy initiatives. Coral researchers believe these political changes pose a direct threat to global conservation.“Removing these protections would have devastating consequences,” Eakin said.